Thrush Aircraft Inc S2R-H80 N6215P accident near Parkin, Arkansas

Probable cause

The improper operation of the rudder pedal adjustment mechanism for an undetermined period of time, which led to the failure of the rudder pedal adjustment track, the detachment of the rudder pedal, and the pilot’s subsequent inability to maintain directional control.

NTSB analysis

The commercial pilot reported that, during the takeoff roll for the agricultural application flight, the right rudder pedal went full forward against the material hopper and that he subsequently could not maintain directional control of the airplane. The airplane subsequently exited the left side of the runway and struck a ditch.

Examination of the airplane revealed that the right rudder pedal had become detached from the rudder pedal adjustment mechanism due to wear on the adjustment track. The Before Starting Engine checklist included a step to adjust and lock the rudder pedals before starting the engine; however, the condition of the rudder system indicated that the airplane had been operated with the rudder pedal forward of the final detent position and against the safety stop rather than in a locked detent position for an undetermined amount of time. The improper adjustment and locking of the rudder pedal adjustment mechanism over time likely led to the excessive wear on the rudder pedal adjustment track, the detachment of the rudder pedal, and the pilot’s subsequent inability to maintain directional control. After the accident, the airplane manufacturer released a service letter detailing the proper use, rigging, and maintenance of the rudder system, including the rudder pedal adjustment mechanism.

Text from the NTSB. Open the NTSB docket for CEN18LA211 for the full record.